FMF - Friends of Minerals Forum, discussion and message board

[Roger Warin]

Hi,
It is strange that the habit of a mineral is so different depending on the origin as it is for brookite.
Brookite crystals have two kinds of crystal habit, one is pyramidal and the other is platy.
The first photo shows an equant brookite crystal from Magnet Cove, Hot Spring Co., Arkansas and the second displays a platy specimen from Baluchistan, Pakistan.
Noted that the Magnet Cove crystal strongly resembles a Hauy's model, consisting of small elementary solids. An external appearance. Strange is it not.

Usually we see a move towards either habit. For brookite it is day and night, the difference is very strong.
Do we know the origin of this feature?
Roger.

[Mark Holtkamp]

Hi Roger,

See this discussion on Mindat:
https://www.mindat.org/mesg-9-15201.html
(Link normalized by FMF)

Mark.